"To complain" is to tell of your aches and pains. Some patients are reluctant to share the details of their discomforts (physical or emotional), since complaining carries connotations of whining, grumbling, moaning and groaning with overtones of dissatisfaction or resentment.
The key issue for me is this: Why are you describing your symptoms?
If doing so is a means to addressing the problem, you are not "complaining" but "reporting." Describing your symptoms helps your physicians understand clearly what ails you. This reporting makes it possible for them to respond with proper evaluations and treatments.
Telling your family that you are in pain helps them understand why you are irritable or why you can't do something as expected. This reporting makes it possible for them to respond in helpful ways.
In contrast, people who tell others about their problems but have no intention of seeking help, accepting offers of help, or making changes that might help are complaining, in the negative sense of the word. And such complaining can be most annoying to hear.
Healthy Survivors don't hesitate to report problems, no matter how big or small, because such reporting begins the healing process. Reporting problems is an essential step toward getting good care and living as fully as possible.